Post navigation

RS18s and violins :: A visit with David

One of the great things about having friends over to see the layout is I never know where the conversation is going to head. I always learn things – and not always about trains.

For instance, on Wednesday my friend David Woodhead visited and I learned about this odd instrument:

(Click on the Stroh Violin to learn more about it on Wikipedia)

Curiously, the instrument in question actually came up in relation to my recently-completed RS18 model:

(Click on the image to read all posts about the RS18)

The connection, of course, was the DCC sound unit I put in the model. David was impressed by the sound, and wanted to know about the speaker I’d used and how I mounted it. Here’s a look at the gubbins:

The speaker is mounted facing up, and the sound escapes the body shell though several avenues – including the various grilles along the sides of the long hood, the exhaust stacks on the top (which are open) and the large rooftop radiator fan.

I mentioned to David that the speaker was ported, but that I was unable to determine whether the port made any difference to the sound. I’d tried a simple test – blocking the port with a finger – and I failed to discern a difference.

That got us talking about ports in speakers for audio systems, secondary sound holes on acoustic guitars and – eventually – the Stroh Violin, which certainly looks like something conjured up by a model railway enthusiast with a well-equipped shop and some spare instruments lying about.

I’ve always thought that the best in our hobby are extremely curious. We love chasing down obscure facts and revel in the unusual – and Wednesday’s visit was yet another example of that.

David and I even ran trains – sort of. Mostly, we talked about various projects over coffee. And that’s always fine.

8 thoughts on “RS18s and violins :: A visit with David”

Yup, must have been something in that coffee! We did cover a lot of ground – lots of projects on both our lists. How ceramic bathroom fittings are cast and programming TCS decoders (thanks for the help there). My, how the time flies!

Interesting blog entry, Trevor! Being an amateur musician myself, and builder and player of the Appalachian Dulcimer (another weird instrument), I enjoyed this. Can you tell me exactly what you meant by the speaker being ported?
Cheers,
Phil

Hi Phil:
Sure thing. If you look closely at the speaker in the third photo in this post, you’ll see that he cone in the enclosure is offset to the right side. At the left side of the enclosure, there’s a round opening. That’s the port. The enclosure is of a Bass-Reflex design. I had to look that up on Wikipedia, so here’s the link:

As the Wikipedia entry notes, this type of speaker uses sound generated from the back side of the speaker to enhance the reproduction of low frequencies.

When I installed this speaker, I did a test – I listened to it while plugging and unplugging the hole. I must admit that during testing, I noticed no difference to the sound quality. That said, this speaker does sound very good – and does deliver a surprising (and pleasant) amount of bass. The locomotive sounds pretty darned grunty!

Thanks for the info, Trevor. The wikipedia article was also very helpful. Did you insert a tube inside the speaker enclosure underneath the port, or was your port just a hole in the surface? I realize that there was probably not much room for a tube, but the wikipedia article indicated that it could be important. I just might experiment with this concept when I find some time to do so – my 40 year career as an acoustics engineer before I retired from GE has me itching to look into this. One of my pet peeves on locomotive sound systems is that they generally sound very “tinny.”

Hi Phil:
I did nothing to the speaker except purchase it. It came mounted in the enclosure with the port already in place. I don’t know if it’s just a hole or whether there’s a tube inside.
Sorry I can’t be more help on this. It does sound remarkably good though – it produces decent bass notes – so I’m assuming somebody did the job right…
Cheers!